Field of the Disclosure
Embodiments of the present invention relate to a display device, and more particularly, to a color filter used for a display device.
Discussion of the Related Art
Recently, various display devices have been developed which are capable of replacing an early-stage display device such as a cathode ray tube (CRT). Liquid crystal display (LCD) device, organic light emitting display (OLED) device, and etc. are examples of such devices.
The organic light emitting display device is provided with a light emitting layer disposed between a cathode for injecting electron and an anode for injecting hole. When the electron generated in the cathode and the hole generated in the anode are injected into the inside of the light emitting layer, exciton is produced by the electron and hole bond. Then, when the exciton falls to a ground state from an excited state, the organic light emitting device becomes luminescent, thereby displaying an image.
The organic light emitting display device may have a structure in which a red (R), green (G) or blue (B) light is emitted from a light emitting layer of an individual pixel without an additional color filter, or may have a structure in which a white (W) light is emitted from a light emitting layer, and a color filter of red (R), green (G) or blue (B) color is formed in each individual pixel.
Hereinafter, an organic light emitting display device with a color filter according to the related art will be described with reference to the accompanying drawings.
FIG. 1 is a cross sectional view illustrating the organic light emitting display device according to the related art.
As shown in FIG. 1, the organic light emitting display device according to the related art may include a substrate 10, a thin film transistor 20, a color filter 30, a planarization layer 40, an anode 50, a bank layer 60, a light emitting layer 70, a cathode 80, and an encapsulation layer 90.
The thin film transistor (T) 20 is provided on the substrate 10. The thin film transistor (T) 20 may include a gate electrode 21, a gate insulating film 22, a semiconductor layer 23, a source/drain electrode 24a/24b, and a passivation film 25 sequentially stacked on the substrate 10.
The color filter 30 may be provided on the passivation film 25. The color filter 30 may be formed of a red (R), green (G), or blue (B) color filter.
The planarization layer 40 is provided on the color filter 30, to thereby planarize a surface of the substrate 10.
The anode 50 is provided on the planarization layer 40. The anode 50 is connected with the drain electrode 24b of the thin film transistor (T) 20 via a contact hole provided in the planarization layer 40 and the passivation film 25.
The bank layer 60 is provided on the anode 50, to thereby define a pixel region. The bank layer 60 is formed in the boundary between each pixel, to thereby form a matrix configuration.
The light emitting layer 70 is provided on the anode 50. The light emitting layer 70 is formed of a plurality of organic material layers, and the light emitting layer 70 emits a white (W) light.
The cathode 80 is provided on the light emitting layer 70.
The encapsulation layer 90 is provided on the cathode 80, wherein the encapsulation layer 90 prevents moisture from being permeated into the inside of the light emitting layer 70.
In case of the organic light emitting display device according to the related art, the white (W) light is emitted from the light emitting layer 70 accordingly as an electron generated in the cathode 80 and a hole generated in the anode 50 are injected into the inside of the light emitting layer 70, and only desired-colored light is emitted through the substrate 10 when the emitted white (W) light passes through the color filter 30, thereby displaying an image.
However, when the image is displayed on the organic light emitting display device according to the related art, a color gamut has limits. That is, in case of the organic light emitting display device according to the related art, a desired color is realized when the white (W) light emitted from the light emitting layer 70 passes through the color filter 30. However, a material for the color filter 30, which has been developed up to now, cannot obtain the color gamut which is capable of satisfying various demands of a user.